VeeamONE Report taking more time to load Veeam Backup & Replication Dashboard like almost 15-20 minutes, but sometimes it will load within fraction of seconds, please let me know what may the root cause.

VeeamONE Environment is,
VeeamONE server installed on a VM, VeeamONE Web UI installed on another VM, there is a seperate VM for VeeamONE database.

How many VMs do you protect with Veeam B&R? Do you have any IIS maintenance tasks that could reset Veeam ONE web site cache data? Another quick question, after a long load process, what happens if you immediately repeat this? Does it also take a lot of time or it loads instantly?